Floor panel comprising a ceramic material or a natural stone

ABSTRACT

The present disclosure relates to a floor panel, comprising a laminate of a core layer, comprising a ceramic or mineral material and a binder a first pair of opposite edges, said first pair of opposite edges comprising complementary coupling parts allowing to mutually couple of plurality of floor panels to each other, a top layer, comprising a ceramic material or a natural stone, wherein the side of the core layer facing the top layer comprises a reinforcement layer, locally having a higher density than the density of the rest of the core layer.

TECHNICAL FIELD

The present disclosure relates to a floor panel, comprising a ceramicmaterial or a natural stone.

BACKGROUND AND SUMMARY

Installed according to the traditional methods known in the field, tilesare adhered to the substrate with mortar or adhesive. Afterinstallation, they are provided with a grout (“grouted”) to provide awatertight surface that can even be applied and used in settings withstanding and running water such as bathrooms. The stability andresistance to temperature and humidity fluctuations inherent to tilesallows the grout's watertightness to be permanent. The result of thistraditional way of installing tiles by grouting fulfils certain needs,given its obvious benefits of waterproofness, aesthetics, and stability.

It is also clear however that tiles have certain disadvantages: themethod of placing tiles is rather laborious, left only to professionals.Special equipment and skill are required, from the surface preparationand reinforcement of subfloors to support the combined weight of mortarand tile, to the layout of the tiles, and the application of a grout.For a grouted installation, a predetermined spacing is left betweentiles that, in the best case, is of uniform width. This spacing is thenfilled with a grout of a chosen color and material, such as a mortar orepoxy. The addition of this grout imposes specific conditions to thesubstrate, at least a minimal weight bearing capacity, and a level offlatness. If the substrate is not prepared sufficiently, the grout oreven the tile might crack under use. Once installed, a grouted floor ispermanent. A tile floor becomes part of the structure, removing itrequires special heavy equipment and could damage the rest of thesubstrate. It is not possible to re-use or repurpose tiles installed insuch a way.

It is known in the field of hard surface flooring to provide the core ofa flooring board such as laminates or PVC flooring with a lockingmechanism. This type of installation with interlocking panels is called“floating” and provides a previously unseen ease with which a floor canbe installed and uninstalled, even by the non professional or homehandyman. To take away the disadvantage of tiles and allow for easyinstallation, removal and replacement, it has been proposed to alsoprovide tiles' edges with this type of locking mechanism. This ishowever not possible to due to the tiles' inherent hardness andbrittleness.

It has therefore been proposed to provide a rigid substrate with a hardsurface veneer formed from ceramic, glass or stone tiles, and to providethis substrate with a locking mechanism to allow for a floatinginstallation, amongst others in U.S. Pat. No. 7,442,423. An imitation ofa grout is even proposed here, aiming to provide the look and feel of atraditional grouted tile. The proposition made by this prior art ishowever overly theoretical and fails to provide details on how to solvethe actual challenges faced when practically realizing such a product.

Firstly, tiles will show movement in a lateral and vertical directionwhen the core is not absolutely stable, putting stress on theinstallation. This stress undermines the tile grout's structuralintegrity, making the installation unfit for use in wet environments. Acoreboard of HDF material as suggested in U.S. Pat. No. 7,442,423 forexample is known to swell or expand with up to 15% when in contact withmoisture measured according to the North American Laminate FloorAssociation's NALFA 3.2 Laminate swelling test, thereby permanentlydamaging the installation. No feasible alternative materials for theenvisioned base are offered. What is more, although the presentdisclosure mentions a “rigid and stable core”, the substrate panel willstill independently change in dimension under temperature changes, asindicated in the present disclosure.

It is known in the floating flooring industry to provide as base,instead of a lignocellulose or wood fiber-based core such as HDF or MDF,alternative substrates based on a polymer such as PP, PE, PVC, PU etc.These are known in the industry to be readily available alternatives,commonly in use for engineered products combining different layers ofplastics. It is possible for example to provide a foamed low densitycore or a high density solid core, common substrates in the laminate andplastic flooring industries. The materials proposed in the art arehowever unsuited for the intended purpose, as the physical property oflignocellulose or plant-based materials is that they move underhumidity, of plastics that they move under temperature fluctuations. Nospecific method of solving this issue is provided.

Secondly, the dimensional changes also put stress on the tile itself.The flexural strength of ceramic, porcelain and stone tiles is so thatslight stress can lead to surface crazing (multiple hairline fractures)and breakage. To illustrate, when glued on a 4 mm solid PVC substrate of2000 kg/m3, a 4.8 mm marble tile showed breaking when heated up from 23C to 60 C, temperatures easily reached in living environments, forexample in a sunroom or behind a window.

Thirdly, the prior art claims that a substrate with lower weight thanthe top layer is beneficial for transportation, installation and theenvironmental. An HDF is proposed to be used as substrate, of a uniformdensity of around 850 kg/m3. As the density of a ceramic tile is around2200 kg/m3, a solid stone around 2800 kg/m3, a porcelain around 2400kg/m3 or higher, significant reductions in weight versus traditionalsolid stone or ceramic tiles can be achieved. However, when combinedwith a substrate of uniform density such as HDF, the impact andindentation resistance of the ceramic tile are insufficient to supportcommercial, or even normal residential, use. Tiles tend to fracture orshow crazing when subjected to higher pressure, especially localizedpressure such as the pressure generated by high heels, because thesubstrate does not provide sufficient support to the top layer,especially when the top veneer is of thinner dimensions.

Details on how to create a stable and rigid core that is viable for use,and a feasible structure that is usable for the intended purpose lack.As a result, there is still no commercially available product in themarket today, illustrating the shortcomings of the current state of thefield.

Prior art documents describe embodiments where a fiberglass layer isadded in between the top and core layers. This is mainly meant toprovide some safety when the top layer breaks, not to prevent the toplayer from breaking, nor to increase or improve the stability of thecore layer. The impact of addition of this layer on stability is alsominimal due to the positioning of the fiberglass layer outside of, notinside, the core layer.

It is therefore a purpose of the current disclosure to provide asubstrate panel that takes away at least some of the shortcomings of theprior art, or at least provides a useful and viable alternative to theprior art.

It is therefore a purpose of the present disclosure to provide a corelayer comprising MgO, Mg(OH)₂, MgSO₄, MgCl₂, CaCO₃, as ceramic ormineral material. These preferred materials show less or no expansion orcontraction due to moisture or temperature fluctuations, to this end themineral or ceramic content of the core layer is preferably at least 80%,and better results may be obtained with around at least 85% mineral orceramic content. These core materials have—unlike plasticcomponents—neither known nor assumed—disadvantages on people's health.It is known that HDF contains large quantities of melamine ureaformaldehyde, a thermosetting resin which poses concerns for humanhealth and the environment as these resins are not degradable, while itswaste management releases harmful toxins into the environment;thermoplastic alternatives likewise raise questions aboutsustainability.

The present disclosure provides a floor panel, comprising a laminate ofa core layer, comprising a ceramic or mineral material and a binder, afirst pair of opposite edges, said first pair of opposite edgescomprising complementary coupling parts allowing to mutually couple ofplurality of floor panels to each other, a top layer, comprising aceramic material or a natural stone, wherein the side of the core layerfacing the top layer comprises a reinforcement layer, locally having ahigher density than the density of the rest of the core layer.

The current disclosure herewith provides extra support to the top layer.This localized higher density improves impact resistance and preventsthe breaking of the top layer. This higher density layer may optionallybe reinforced with a fiberglass layer that is locally incorporatedwithin the substrate material and is located nearby the top surface ofthe support layer. Any other fiber layer of similar physical propertiesmay of course also be considered.

The reinforcement layer may be interpreted as a higher density toplayer, or a crust layer, that can be formed in an extrusion process,with the top and/or bottom surfaces being increased in density through acooling process, or deposited in layers to the substrate in form of aslurry of differing density and then dried, or added in layers ofdifferent density. Preferably its density is at least 5% higher than therest of the core, more preferably more than 10% higher, and even morepreferred more than 20% higher.

The present disclosure herewith provides a ceramic tile with aninterlocking mechanism on the sides that can be installed as a floatingfloor, that is able to withstand impacts, stresses in transportation,fluctuations in humidity and temperature, and is suitable for use incommercial settings.

In general, according to the present disclosure, a top layer with athickness between 1 and 10 mm is preferred according to the presentdisclosure, and a core with a thickness between 2 and 10, and preferablyabout 6 mm is preferred. A total product thickness of 8-15 mm is furtherpreferred. Good stability results under fluctuations in humidity andtemperature were obtained with an 8 mm MgO-based board with an overalldensity of 1200 kg/m3 and a crust of 1600 kg/m3 density of 2 mm thicknear the top surface and reinforced with a fiberglass mesh. It is ofcourse possible to change the fiberglass to a natural fibre to achieve acompletely plastic-free construction, or to add more reinforcing layers,such as near the bottom surface of the panel, to attune total stabilityof the board. Yet a further improvement can be obtained by applying atleast one reinforcing fiberglass mesh, but preferably two such layers,with a second near the bottom surface of the panel, preferablyincorporated in the reinforcing layer: in this embodiment dimensionalstability after 24 hr submersion in water was proven to be limited to0.03% length- and width-wise, and a thickness swelling of less than0.01% was noted when measured according to NALFA 3.2. The expansion ratefrom 23 C-60 C was 0%, contraction after heating up to 80 C measuredaccording to ISO 23999 was measured to be 0%.

The complementary coupling parts may in particular comprise aclick-coupling, that is a coupling that snap-fits when two tiles areengaged against each other. Addition of a small quantity oflignocellulose fibers to the core adds sufficient elasticity to thelocking mechanism necessary to allow for a smooth engagement of thelock. The lignocellulose content is however preferably less than 15%,and most preferably less than 10%, to avoid swelling under conditions ofmoisture and issues with mold or fungus. Satisfactory results thatobtained a fungus resistance of grade 0 (no fungus growth) when measuredaccording to ASTM G21—Standard Practice for Determining Resistance ofSynthetic Polymeric Materials to Fungi were obtained with alignocellulose content of around 9%. A lignocellulose content above 8%is preferred in order to obtain enough flexibility for coupling partsthat need to bend for a click.

It is known in the art to further provide a bio-ceramic material coatingto a core layer for antifungal and deodorizing effects. This isnecessary as lignocellulose or plant-based panels are sensitive to moldor fungus growth. Plastic-based substrates are also sensitive to mold orfungus growth due to the addition of vinylizers or plasticizers, whichserve as nutrition to fungus. A regular vinyl or PVC flooring containingplasticizers rates around grade 1-2 (slight growth of fungus) whentested according to ASTM G21. The current disclosure proposes a mineralor ceramic substrate comprising or even being substantially made of MgO,Mg(OH)₂, MgSO₄, MgCl₂, CaCO₃ or alternative materials of similarproperties that is, as a result, naturally antifungal when tested toASTM G21 with a result of grade 0 (no fungus growth).

In a further embodiment of the present disclosure, the surface area ofthe top layer is smaller than the surface of the core layer. Whenassembling a floor from these panels, the impression of a grout isgiven, formed by the uncovered and thus visible parts of the core layer.The spacing created is consistent and easily maintained due to theprefabricated nature of the panels. It is possible to then grout thisspacing with mortar or an epoxy grout if required, or to use thesubstrate as an imitation grout. In this case, the substrate ispreferably level with the top layer on at least two sides, with theimitation grout on at least one side. It is possible to manufacture agrout with a certain color for aesthetic effect, or to add a color inthe manufacturing process, or to add a finish with a certain color tothe surface of the grout.

An additional backing layer may further be present at the side from thecore layer facing away from the top layer, having acoustic dampeningproperties. To this end, a low density layer can be considered of atleast 85 kg/m3, preferably more than 130 kg/m3, such as with a foamstructure in which closed or open cells are present. This foam structureis typically obtained by adding blowing agents to a melt, before it isformed and hardened into the final shape. Common in the field are foamedlayers basically composed of ethylene vinyl acetate, irradiationcross-linked polyethylene or similar alternative materials such aspolyvinyl chloride. Out of environmental considerations, natural optionssuch as a cork layer or a layer of recycled PET (polyethyleneterephthalate) could be considered. Another benefit of thissound-dampening layer is the absorption and levelling of substrateirregularities, even further reducing the chance of a breaking toplayer.

1. Panel for assembling a floor or wall covering, comprising: a corelayer, comprising: a ceramic or mineral material and a binder; at leastone pair of opposite edges, said pair of opposite edges comprisingcomplementary coupling parts allowing to mutually couple a plurality offloor panels to each other; and a top layer, comprising a ceramicmaterial, a tile, a porcelain ceramic, a natural stone, or a mosaic;wherein: a side of the core layer facing the top layer comprises areinforcement layer, locally having a different density than a densityof the rest of the core layer.
 2. The floor panel according to claim 1,wherein the reinforcement layer has a density that is higher than thedensity of the rest of the core layer.
 3. The floor panel according toclaim 2, wherein the reinforcement layer has a density that is at least5%, 10%, or 20% higher than the density of the rest of the core layer.4. The floor panel according to claim 1, comprising a fibre mesh locatednear a surface of the reinforcement layer.
 5. The floor panel accordingto claim 1, wherein the reinforcement layer is a crust layer.
 6. Thefloor panel according to claim 1, wherein the core layer has a lowerdensity than the top layer.
 7. The floor panel according to claim 1,wherein the complementary coupling parts comprise a click-coupling. 8.The floor panel according to claim 1, wherein the core layer comprisesat least one of MgO, Mg(OH)₂, MgSO₄, MgCl₂, and CaCO₃ as the ceramic ormineral material.
 9. The floor panel according to claim 7, wherein amineral or ceramic content of the core layer is at least 50%, at least75%, or at least 85%.
 10. The floor panel according to claim 1, whereinthe core layer comprises lignocellulose as a binder between 8% and 15%or at 9% or 10%.
 11. The floor panel according to claim 1, wherein thetop layer comprises a stone veneer, or a porcelain tile.
 12. The floorpanel according to claim 1, wherein the top layer has a thicknessbetween 1 and 12 mm and the core layer has a thickness between 2 and 10mm or 6-8 mm.
 13. The floor panel according to claim 1, wherein asurface area of the top layer is smaller than a surface area of the corelayer.
 14. The floor panel according to claim 1, wherein on at least oneside the core layer is visible to imitate a grout.
 15. The floor panelaccording to claim 1, wherein a grout can be applied for a waterproofinstallation.
 16. The floor panel according to claim 1, wherein at leastone part of the core layer that is not covered by the top layer has apre-applied finish to imitate a grout.
 17. The floor panel according toclaim 1, wherein a backing layer is present at a side of the core layerfacing away from the top layer, having acoustic dampening and levellingproperties.
 18. Panel for assembling a floor or wall covering,comprising: a core layer, comprising a ceramic or mineral material and abinder; at least one pair of opposite edges, said pair of opposite edgescomprising complementary coupling parts allowing to mutually couple aplurality of floor panels to each other; and a top layer, comprising aceramic material, a tile, a porcelain ceramic, a natural stone, or amosaic; wherein a side of the core layer facing the top layer comprisesa reinforcement layer, locally having a different density than a densityof the rest of the core layer, wherein the reinforcement layer has adensity that is higher than the density of the rest of the core layer,wherein the reinforcement layer has a density that is at least 5%higher, more preferably 10% higher, and most preferably at least 20%higher than the density of the rest of the core layer, wherein a floorpanel comprising a fibre mesh is located near a surface of thereinforcement layer and/or wherein the reinforcement layer is a crustlayer, and/or wherein the core layer has a lower density than the toplayer; and/or wherein the complementary coupling parts comprise aclick-coupling, and/or wherein the core layer comprises MgO, Mg(OH)₂,MgSO₄, MgCl₂, CaCO₃ as the ceramic or mineral material, wherein amineral or ceramic content of the core layer is at least 50%, morepreferably more than 75%, most preferably at least 85%, and/or whereinthe core layer comprises lignocellulose as a binder, in particularbetween 8% and 15% and more preferably 9% or 10%, and/or wherein the toplayer comprises a ceramic, a natural stone, a stone veneer, a mosaic ora porcelain tile, and/or wherein the top layer has a thickness between 1and 12 mm and the core layer has a thickness between 2 and 10 mm, andpreferably about 6-8 mm, and/or wherein a surface area of the top layeris smaller than a surface area of the core layer; and/or wherein on atleast one side the core layer is visible to imitate a grout, and/orwherein a grout can be applied for a waterproof installation, and/orwherein at least one part of the core layer that is not covered by thetop layer has a pre-applied finish to imitate a grout, and/or wherein abacking layer is present at a side of the core layer facing away fromthe top layer, having acoustic dampening and levelling properties.